Dream 6800 40th Anniversary

Dream 6800 40th Anniversary

Dream 6800 40th Anniversay vintage computer,  Has been designed by David Fry (UK), has completed an elegant re-design of the DREAM using a double-sided PCB (pictured below). It has an on-board switchmode regulator for the +5V supply and a DC/DC converter for negative 5V. Memory has been upgraded to 4KB using two 6116 RAM chips. The EPROM can be a 2716 or 2732 type. Otherwise, David’s design remains faithful to the original. The download includes KiCad PCB design files and Gerber files for board fabrication.

 

Origins of the Dream:

 

The “DREAM-6800” was a popular build-it-yourself computer which I designed in 1978. The project was published in Electronics Australia magazine in 1979. The Dream was a ridiculously simple hobby computer with 2K bytes of memory that played game programs on a TV. The 1KB ROM (1024 bytes!) contained a simple interpretive programming language known as “CHIP-8”, devised by Joe Weisbecker of RCA Labs.

This inspired the DREAM-6800 which I admit was a blatant rip-off of the VIP concept, except that the Dream video controller circuit was designed around “discrete” 74-series and 4000-series logic IC’s to generate a PAL-compatible display format (50Hz vertical refresh rate, vs 60Hz for the VIP). And my audio tape modem circuit design was 100% original and much simpler than both the VIP and D2 kit tape circuits.

I submitted a much simplified and refined Dream 6800 design to E/A, including CHIP-8 interpreter in EPROM and a bunch of CHIP-8 games (also ripped off from the VIP). This time Jim liked the idea… a DIY project he could spread over several months, without the magazine having to do any development work, with all the text provided on a silver plate! By the way, I did ask permission from Joe Weisbecker to clone his CHIP-8 language and a few games. He was really chuffed that his idea had caught on “down under”.

In hindsight, I regret down-grading the video format to 64 x 32 pixels. This was done not only to minimize price and board size, but also for CHIP-8 program compatibility. But with RAM prices dropping fast, I should have made it 128 x 64 pixels (1KB of RAM), at least. The PCB would have been bigger, but still not as big as the Cosmac VIP. Also, the VIP game programs could have been modified to run on a larger screen format, but I was under pressure from E/A to finish the articles for publication. Annoyingly, by the time E/A was ready to publish the first instalment, higher density RAM and (single 5V) EPROM chips were readily available. But a further delay due to a design revision would have been unacceptable.

 

Here is my completed Dream 6800 40th Anniversay vintage computer

 

 

One Response to “Dream 6800 40th Anniversary”

  1. John says:

    I built the original one of these when I was a kid (got the board of a pcb manufacturer in Newmarket) , my first “working” computer. 🙂

    Can you contact me please – I’m interested in getting some of the new boards if you have any.

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